4
they're both extremely good, but RDR2 would be better if you don't know if he has played Witcher 1 or 2 first. RDR2's story stands alone.
there is no wrong choice
Story telling, yes. The story is instantly good and could be a live action tbh. Combat/Adventure No.
Seconding this. I love RDR2 a lot. Witcher 3 feels better when you’ve played the first two.